I have a 2003 dodge ram 1500 and i have 22" rims on right now but i have my stock 17" for winter and I was wondering what is the biggest tire size i can go without missing up the mph?

 

Usually when you go with larger rims your tire diameter decreases thus keeping your overall size in the same ballpark. Unless your going with a lift and offroad tires you shouldnt have to worry.

Oops didnt read your post very well. Your already on 22's. What series tire 40 or 45s ? Neither should affect your speedo unless your going with offroad style which will probably require a lift